Anatomy and Physiology

    Muscles
    Which of the events below is the FIRST to occur prior to a muscle cell contracting?
    The release of Ca from where it is stored (in the SR) is necessary before the active binding site of actin can be exposed.
    Author: rikazzz Comment
    Biomechanics
    Fixed traction may be applied by a device such as a “Thomas splint”. In this case, the counter-traction force is supplied by:
    Fixed traction does not involve cords and hanging masses. The Thomas splint involves “stretching” the leg between the foot and the pelvis.
    Author: rikazzz Comment
    Nervous System
    An image of the cross-section of a spinal cord would show “anterior (or ventral) horns”. What is in that region?
    The “horns” contain grey matter which is the cell bodies of motor neurons. The dorsal horns contain sensory nuclei (cell bodies of neurons).
    Author: rikazzz Comment
    Cardiovascular System
    According to Poiseuille’s law, volume flow rate through a blood vessel is proportional to its radius to the fourth power (V ∝ R4). If an atheroma reduces the radius of an artery from 4 to 2 mm, what effect would this have on the blood flow through the artery?
    2 mm is half of 4 mm and according to Poiseuille’s law: V ∝ (1/2)4 = 1/16
    Author: rikazzz Comment
    Body Temperature, Energy and Heat Loss
    By what means does a person sitting in the shade of a tree on a very hot dry summer day lose most of their heat? By:
    On a hot day, sweating will be occurring, and its evaporation into a dry atmosphere would produce cooling. As the surroundings and air are hot, not much heat will be lost by radiation, convection or conduction.
    Author: rikazzz Comment
    Chemistry for Physiology
    A buffer solution having a pH of 8.5 has a small amount of strong acid added to it. What is its pH value likely to be closest to?
    A buffer solution resists change to its pH. This means that its pH will change very little, but it will change slightly. As acid has been added, its pH will drop by a small amount.
    Author: rikazzz Comment
    Gastrointestinal System
    Kupffer cells are macrophages. Where are they found?
    They are in the liver sinusoids (capillaries).
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    Endocrine System
    Which of the following secretes growth hormone?
    The anterior lobe produces and releases GH.
    Author: rikazzz Comment
    Nervous System
    Myopia may be corrected with a lens that is:
    In myopia (near-sightedness) close objects are in focus but distant ones are not. It may be corrected by using a concave (diverging) lens.
    Author: rikazzz Comment
    Body Temperature, Energy and Heat Loss
    What may the “thermal energy” of the particles in an object be defined as?
    In gases, thermal energy is energy stored as kinetic energy, rotational motion, vibrational motion and associated potential energies. In other substances, in cases where some of the thermal energy is stored in atomic vibration or by increased separation of particles having mutual forces of attraction, the thermal energy is partitioned between potential energy and kinetic energy.
    Author: rikazzz Comment